FIG. 1 shows a conventional fuel-injection device by way of example. Here, a flat intermediate element is provided on a fuel injection valve installed in a receiving bore of a cylinder head of an internal combustion engine. In the conventional manner, such intermediate elements are positioned as support elements in the form of a washer on a shoulder of the receiving bore of the cylinder head. Intermediate elements of this kind are meant to compensate for production and installation tolerances and to ensure that transverse forces will not affect the mounting even if the fuel injector is positioned at a slight tilt. The fuel-injection device is especially suitable for use in fuel-injection systems of mixture-compressing internal combustion engines having externally supplied ignition.
Another type of simple intermediate element for a fuel-injection device is described in German Patent No. DE 101 08 466 A1. The intermediate element is a washer having a circular cross-section, which is disposed in a region in which both the fuel injector and the wall of the receiving bore in the cylinder head extend in the form of a truncated cone, the washer being used as a compensating element for mounting and supporting the fuel injector.
Intermediate elements for fuel-injection devices that are more complicated and much more resource-intensive in the production are also described in German Patent Nos. DE 100 27 662 A1 and DE 100 38 763 A1, and European Patent No. EP 1 223 337 A1, among others. All of these intermediate elements are distinguished by being constructed of multiple parts or multiple layers and in some cases are meant to assume sealing and damping functions. The intermediate element described in German Patent No. DE 100 27 662 A1 includes a base and carrier body, into which a sealing means that is penetrated by a nozzle body of the fuel injector is inserted. In German Patent No. DE 100 38 763 A1, a multi-layered compensating element is described, which is composed of two rigid rings and an elastic intermediate ring sandwiched between them. This compensating element allows both for tilting of the fuel injector in relation to the axis of the receiving bore over a relatively large angular range and a radial displacement of the fuel injector from the center axis of the receiving bore.
An intermediate element that likewise has multiple layers is also described in European Patent No. EP 1 223 337 A1; this intermediate element is composed of a plurality of washers which are made from a damping material. The damping material of metal, rubber or PTFE is selected and configured so that noise damping of the vibrations and the noise generated by the operation of the fuel injector is possible. However, the intermediate element must have four to six layers for this purpose in order to achieve the desired damping effect.
Furthermore, to reduce noise emissions, U.S. Pat. No. 6,009,856 A1 suggests to surround the fuel injector by a sleeve and to fill up the created interspace with an elastic, noise-damping mass. However, this type of noise damping is very resource-intensive, difficult to assemble and costly.